• Journal of the Korean Chemical Society
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• v.28 no.4
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• pp.251-258
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• 1984

The mechanism of photosensitization and the affect of binder on dye-sensitized ZnO have been studied by surface photovoltage spectroscopy. It has been found that the value of energy trapping level $E_{t1}$ on ZnO is 1.12eV (${\lambda$ = 1,100nm) and that of energy trapping level $E_{t2}$ on dye-sensitized ZnO is 0.99eV (${\lambda$ = 1,250nm) which is shifted towards a longer wavelength. The effect of binder on ZnO has been increased the efficiency of surface photovoltage, but it does not effect the values of energy trapping level. The acid-type dyes agree well with the prediction based on an electron transfer mechanism. The desensitization of the Na salt-type dyes for the intrinsic photoresponse of zinc oxide can be explained by energy transfer mechanism. It has been obtained that the dye-sensitized ZnO indicates the possibility of electrophotographic photosensitizer for the infrared range of light.

• KSBB Journal
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• v.24 no.5
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• pp.469-476
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• 2009

The antioxidant activities of two crude extracts ($CH_2Cl_2$ and MeOH) and their solvent fractions (n-hexane, 85% aq. MeOH, n-BuOH, and $H_2O$ fractions) from Corydalis heterocarpa were determined by evaluating authentic $ONOO^-$ and $ONOO^-$ generated from SIN-1 (3-morpholinsydnonimine) in vitro as well as by measuring the degree of occurrence of intracellular reactive oxygen species (ROS) and nitric oxide (NO). Scavenging activities of solvent fractions on authentic $ONOO^-$ increased in the order of n-BuOH > 85% aq. MeOH > $H_2O$ > n-hexane fractions, while those on $ONOO^-$ generated from SIN-1 increased in the order of n-BuOH > 85% aq. MeOH > $H_2O$ > n-hexane fractions. In addition, all solvent fractions effectively inhibited the intracellular ROS and NO levels. The n-BuOH fraction especially exhibited the strongest ROS scavenging effect. Further purification of n-BuOH fraction led to the isolation of cnidimoside A, which presented the potent ROS scavenging effect at $10\;{\mu}M$. From these results, extracts of C. heterocarpa and its component, cnidimoside A, were predicted to be potentially useful as ingredients for protecting against oxidation.

• Korean Journal of Materials Research
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• v.14 no.12
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• pp.876-884
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• 2004

This study was to investigate whether the bioactivity of the anodized and hydrothermally treated Ti-6Al-7Nb alloy were affected by the time of hydrothermal treatment. Anodizing was performed at current density 30 $mA/cm^2$ up to 300 V in electrolyte solutions containing $DL-{\alpha}-glycerophosphate$ disodium salt hydrate $(DL-{\alpha}-GP)$ and calcium acetate (CA). Hydrothermal treatment was done at $300^{\circ}C$ for 30 min, 1 hr, 2 hrs, and 4 hrs to produce a thin film layer of hydroxyapatite (HA). The bioactivity was evaluated from HA formation on the surfaces in a Hanks' solution with pH 7.4 at $36.5^{\circ}C$ for 10, 20, and 30 days. Anodic oxide films were porous with pore size of $1\sim4{\mu}m\;and\;3\sim4{\mu}m$ thickness. The anodic oxide films composed with strong anatase peak with presence of rutile peak, and showed the increase in intensity of anatase peak after hydrothermal treatment. It was shown that the intensity of anatase peak increased with increasing the time of hydrothermal treatment but was no difference in rutile peak. The corrosion voltage was the highest in the group of hydrothermal treatment for 2 hrs (Ecorr: -338.6 mV). The bioactivity in Hank's solution was accelerated with increasing the time of hydrothermal treatment.

• Journal of the Korean Ceramic Society
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• v.42 no.12 s.283
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• pp.827-832
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• 2005

In this study, thin electrolyte layer was prepared by 8YSZ ($8mol\%$ Yttria-Stabilized Zirconia) slurry dip and sol coating onto the porous anode support in order to reduce ohmic resistance. 8YSZ polymeric sol was prepared from inorganic salt of nitrate and XRF results of xerogel powder exhibited similar results $(99.2\pm1wt\%)$ compared with standard sample (TZ-8YS, Tosoh Co.). The dense and thin YSZ film with $1{\mu}m$ thickness was synthesized by coating of 0.7M YSZ sol followed by heat-treatment at $600^{\circ}C$ for 1 h. Thin film electrolyte sintered at $1400^{\circ}C$ showed no gas leakage at the differential pressure condition of 3 atm.

• Polymer(Korea)
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• v.28 no.6
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• pp.455-459
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• 2004

Ionic conductivities of poly(ethylene oxide) (PEO)-based electrolytes are in a considerable inconsistency in many papers, varying more than three orders of magnitude for just same compositions. In PEO-salt-ceramic composite electrolytes, it has been also reported that the conductivity can be variant by almost three orders of magnitude according to thermal treatment and it has been regarded as a consequence of polymer-ceramic particle interaction. In this paper, we present a more systematic study on the change of ionic conductivity for ceramic-free PEO$_{10}$LiClO$_4$ polymer electrolytes, and found that the ionic conductivity can be variant more than hundred times according to thermal history. The slow recrystallization kinetics of PEO polymer is discussed to be responsible for the thermal history effect. Present results reveal that the effect of ceramic filler is not a main cause of the conductivity relaxation phenomenon.n.

• The Korea Journal of Herbology
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• v.25 no.2
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• pp.89-98
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• 2010

Objective : The aim of this study was to determine whether methanol extract of Keum-Ryung-Ja-San (KRJS) inhibit production of NO, $PGE_2$, iNOS, COX-2 and pro-inflammatory cytokines in lipopolysaccharide (LPS)-treated RAW 264.7 macrophages. Methods : Cytotoxic activity of extracts on RAW 264.7 cells was measured using 5-(3-caroboxymeth-oxyphenyl)-2H-tetra-zolium inner salt (MTS) assay. The nitric oxide (NO) production was measured by Griess reagent system. And proinflammatory cytokines and PGE2 were measured by ELISA kit. The levels of inducible nitric oxide synthase (iNOS), cyclooxygenase-2(COX-2), $I{\kappa}-B-\alpha$ and nuclear NF-${\kappa}B$ p65 expression were detected by western blot. Results : Our results indicated that methanol extract of KRJS significantly inhibited the LPS-induced NO, $PGE_2$ production and iNOS, COX-2 expression accompanied by an attenuation of TNF-$\alpha$, IL-$1{\beta}$ and IL-6 production in RAW 264.7 cells. Moreover, methanol extract of KRJS treatment also blocked LPS-induced NF-${\kappa}B$ activation. Conclusion : These findings indicate that methanol extract of KRJS inhibits the production of pro-inflammatory mediators and cytokines via suppression of NF-${\kappa}B$ activation. Take together, these results indicate that methanol extract of KRJS has the potential for use as an agent of anti-chronic inflammatory diseases.

• Journal of the Korean institute of surface engineering
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• v.54 no.5
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• pp.238-247
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• 2021

PEO (plasma electrolytic oxidation) was applied to modify the surface of AZ31 magnesium alloy in this study. The mixed solution of sodium hydroxide (NaOH) and sodium silicate (Na₂SiO₃) was used as the electrolyte, and 0 - 0.05 g/L of Ca-GP (Glycerol Phosphate Calcium salt) was added in the electrolyte as an additive. PEO treatment was conducted at a current density of 30mA/cm² for 5 minutes using a DC power supply. The surface properties were identified by SEM, XRD and surface roughness analyses, and the corrosion resistance was evaluated by potentiodynamic polarization and immersion tests. In addition, the biocompatibility was evaluated by immersion test in SBF solution. As the concentration of Ca-GP was increased, the surface morphology was denser and more uniform, and the amount of Ca and the thickness of oxide layer increased. Only Mg peak was observed in XRD analysis due to very thin oxide layer. The corrosion resistance of PEO-treated samples increased with the concentration of Ca-GP in comparision with the untreated sample. In particular, the highest corrosion resistance was identified at the group of 0.04g Ca-GP through potentiodynamic polarization and immersion tests in saline solution (0.9 wt.%NaCl). During the immersion in saline solution, pH rapidly increased at the beginning of immersion period due to rapid corrosion, and then increase rate of pH decreased. However, the pH value in the SBF temporarily increased from 7.4 to 8.5 during the day, then decreased due to the inhibition of corrosion with HA(hydroxyapatite) formation.

• Journal of Applied Biological Chemistry
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• v.62 no.1
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• pp.57-66
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• 2019

The ethyl acetate fraction of Bat Faeces (Ye Ming Sha: natural products used in Chinese Medicine) after fermentation (EFBF-AF) showed enhanced anti-oxidative effects in 2,2-diphenyl-1-picrylhydrazyl and 2,2'-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt assays. Fermentation of the Bat Faeces by using the crude enzyme extract from Aspergillus kawachii, significantly increased the anti-inflammatory effects. Fermented Bat Faeces markedly inhibited nitric oxide production, inducible nitric oxide synthase, and cyclooxygenase-2 expression in lipopolysaccharide (LPS)-stimulated RAW 264.7 macrophage cells. The EFBF-AF reduced the nuclear translocation of nuclear factor kappa B ($NF-{\kappa}B$) via $IKK{\alpha}$ and $I{\kappa}B{\alpha}$ phosphorylation, and decreased the phosphorylated the extracellular signal-regulated kinases (ERK) and p38 expression in LPS-treated RAW 264.7 macrophages. In addition, the EFBF-AF suppressed the expression of pro-inflammatory genes, such as interleukin-$1{\beta}$, interleukin-6, and tumor necrosis $factor-{\alpha}$. These results suggest that fermented Bat Faeces may suppress pro-inflammatory responses in LPS-stimulated RAW 264.7 macrophages cells via ERK, p38 mitogen-activated protein kinase and $NF-{\kappa}B$ signaling pathways.

• Korean Journal of Materials Research
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• v.29 no.4
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• pp.241-251
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• 2019

There are several manufacturing techniques for developing thermionic cathodes for vacuum ultraviolet(VUV) ionizers. The triple alkaline earth metal emitters(Ca-Sr-Ba) are formulated as efficient and reliable thermo-electron sources with a great many different compositions for the ionizing devices. We prepare two basic suspensions with different compositions: calcium, strontium and barium. After evaluating the electron-emitting performance for europium, gadolinium, and yttrium-based cathodes mixed with these suspensions, we selected the yttrium for its better performance. Next, another transition metal indium and a lanthanide metal neodymium salt is introduced to two base emitters. These final composite metal emitters are coated on the tungsten filament and then activated to the oxide cathodes by an intentionally programmed calcination process under an ultra-high vacuum(${\sim}10^{-6}torr$). The performance of electron emission of the cathodes is characterized by their anode currents with respect to the addition of each element, In and Nd, and their concentration of cathodes. Compared to both the base cathodes, the electron emission performance of the cathodes containing indium and neodymium decreases. The anode current of the Nd cathode is more markedly degraded than that with In.

• The Korea Journal of Herbology
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• v.24 no.2
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• pp.49-56
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• 2009

Objectives : Inflammation is important event in the development of vascular diseases including hypertension, atherosclerosis, and restenosis. Bodusan (BDS) was a traditional Korean herbal medicine and widely used in treatment of gastrointestinal complaint and stomach ulcer. The aim of this study was to determine whether BDS and its components inhibit production of nitrite, PGE2 and proinflammatory cytokines in lipopolysaccharide (LPS)-treated RAW 264.7 macrophages. Methods : Cytotoxic activity of BDS and its components on RAW 264.7 cells was using 5-(3caroboxymcrophages. eth-oxyphenyj)-2H-tetra-zolium inner salt (MTS) assay. The nitric oxide (NO) production was measured by Griess reagent system. And proinflammatory cytokines were measured by ELISA kit. The levels of inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) expression were detected by western blot. Results : Our results indicated that BDS and its components significantly inhibited the LPS-induced NO and PGE2 production. Moreover. BDS and its components inhibited iNOS and COX-2 expression accompanied by an attenuation of TNF-${\alpha}$, IL-11${\beta}$, IL-6 and MCP-1 formation in macrophages. Conclusions: These results indicate that BDS and its components have potential as an anti-inflammatory agent.